Medicare Advantage

What’s Changing in Montana Medicare Advantage for 2027: 12 Plans Leaving, 9 Changing

HELENA — Montana's Medicare Advantage lineup is shrinking for the 2027 plan year, and every county in the state will see at least one plan either leave or change. According to the CMS Medicare Advantage Landscape Source Files, the number of Medicare Advantage plans offered somewhere in Montana drops from 32 for 2026 to 23 for 2027. Twelve plans are leaving, nine are changing in at least one county, three are new, and eleven are continuing unchanged. Two carriers — Blue Cross and Blue Shield of Montana and PacificSource Medicare — have no Montana plans listed for 2027, and one carrier, Range Health, is new to Montana for 2027.

Medicare AdvantageMontana

Here is what the CMS files say, what the key dates are, and how to figure out whether the plan you have today is one of the ones affected.

What the statewide numbers mean

The CMS Landscape files list every Medicare Advantage plan offered in each county, each year. Comparing the CY2026 file to the CY2027 file produces the statewide picture above. Each plan is counted once statewide, no matter how many counties it serves.

A plan is counted as "leaving" if it was offered somewhere in Montana for 2026 and is offered nowhere in Montana for 2027. There are 12 of those. A plan is counted as "changing" if it is offered in both years but differs in at least one county on premium, drug deductible, plan type or plan name as recorded in the CMS file. There are 9 of those. The files also show 3 plans new to Montana for 2027 and 11 that continue unchanged.

Two carriers appear in the 2026 file but not the 2027 file for Montana: Blue Cross and Blue Shield of Montana, and PacificSource Medicare. One carrier appears in the 2027 file for Montana for the first time: Range Health.

If your plan is leaving

If your current Medicare Advantage plan is among the 12 leaving Montana for 2027, your carrier is required to send you a non-renewal notice. You have two protections.

First, the Annual Enrollment Period (AEP) runs October 15 – December 7, 2026. Anything you choose during AEP takes effect January 1, 2027. That is the simplest path: pick a new plan before December 7 and your coverage transitions on New Year's Day.

Second, if your plan is not renewed, Medicare gives you a Special Enrollment Period (SEP) that runs through the end of February 2027. That window lets you enroll in a different Medicare Advantage plan, or return to Original Medicare and add a stand-alone Part D drug plan, after January 1.

If you do nothing and your plan is leaving, you will generally revert to Original Medicare on January 1, 2027, without drug coverage attached — which is why the SEP exists.

If your plan is changing

If your plan is among the 9 that are continuing but changing in at least one county, you will receive an Annual Notice of Change (ANOC) from your carrier, typically by the end of September 2026. The ANOC is the official document that lists exactly what is different for 2027 compared with 2026 — including anything the CMS file flagged as a change in premium, drug deductible, plan type or plan name.

The important thing to know: the CMS file tells us a change exists, but the ANOC has the specifics for your plan in your county. Read it carefully. If you do nothing, you stay enrolled in your plan for 2027 with the changes described in the ANOC applied automatically.

The counties with the most change

All 50 Montana counties see at least one plan leave or change for 2027. The counts below come straight from the CMS Landscape comparison and include every plan that served the county for 2026, whether it is leaving or changing for 2027.

• Yellowstone County: 12 leaving, 6 changing
• Flathead County: 10 leaving, 7 changing
• Cascade County: 6 leaving, 7 changing
• Glacier County: 10 leaving, 3 changing
• Golden Valley County: 10 leaving, 3 changing
• Lake County: 9 leaving, 3 changing
• Chouteau County: 7 leaving, 3 changing
• Judith Basin County: 6 leaving, 4 changing

A high "leaving" count in your county does not mean your specific plan is leaving — it means more of your neighbors will be shopping. Check your own mail from your carrier.

What to do before December 7

A short checklist for Montana enrollees between now and December 7, 2026:

1. Watch the mail in September and October 2026 for either a non-renewal letter (your plan is leaving) or an Annual Notice of Change (your plan is continuing, with or without changes). 2. If you got a non-renewal letter, remember you have both the AEP through December 7, 2026, and the SEP through the end of February 2027. 3. If you got an ANOC, read the 2027 section and compare it to what you have now. If everything still fits, you do not have to do anything. 4. If you want to compare options, use the official Plan Finder at Medicare.gov, which draws on the same CMS Landscape and Plan Finder data. 5. Make any change you want effective January 1, 2027 by December 7, 2026.

Where to get free help

You do not have to sort through this alone, and you do not have to pay anyone to help. Three free, unbiased resources:

• Medicare.gov — the official Plan Finder lets you enter your ZIP code and your prescriptions and see every plan available to you.
• 1-800-MEDICARE (1-800-633-4227) — available 24/7 for questions about enrollment, notices and your options.
• The State Health Insurance Assistance Program (SHIP) — Montana's SHIP offers free, one-on-one counseling with trained volunteers who do not sell insurance.